Sun Drying of Sultana Grapes

Abstract

In this paper, an experimental investigation is presented on natural sun drying of Sulruna grapes. in drying experiments, a new pretreatment solution was employed to decrease the drying time and to obtain better quality products. In addition to this solution, grape drying experiments in the pretreated form with potasa solution -the most common mixture in Turkey for grape drying- and in the untreated form were carried out. The measurements of weight loss and dry matter (and brix) during drying experiments, and the color, pH and total acidity measurements at the end of drying experiments were carried out. The results show that the total drying period for grapes pretreated with the present solution was 128 hr while the drying periods for the cases, e.g., pretreated with potasa solution and untreated were 176 hr and 436 hr. This means that the drying rate for pretreated grapes with the present solution was 1.375 times faster than the pretreated case with potwa and 3.4 times faster than the untreated case. In light of the results obtained here. it is clear that the present solution is a very good alternative for grape drying applications and will be beneficial to the relevant industry and people.